The present invention generally relates to a method and apparatus for regulating patient temperature, and more particularly, to a heat exchange catheter for insertion into the colon.
There are a variety of medical conditions where it is desirable to regulate body temperature by either warming, cooling or maintaining the temperature of a patient. Examples of medical conditions where temperature regulation is warranted include accidental hypothermia, fever, therapeutic hypothermia, and warming or maintenance of normothermia during surgery or recovery.
Therapeutic hypothermia has proven useful in the treatment of stroke, SAH (subarachnoid hemorrhage), head injury and in other ailments. During surgery, a hypothermic state may reduce swelling, blood loss, and other adverse bodily reactions to surgery. It is expected that other therapeutic benefits of regulating the body temperature will manifest according to further development in this field.
U.S. Pat. No. 6,146,411 describes a system that relies on an indwelling heat exchange catheter for regulating a patient""s temperature. The catheter inserts into the central vascular of a patient, heats or cools the blood supply, and thereby regulates the patient temperature.
U.S. Pat. No. 6,126,684 describes several types of vascular heat exchange catheters. One catheter includes a fluid that is heated or cooled from an external source and circulates through the catheter to exchange heat. A balloon is disclosed as one way of providing a heat exchange element, through which, the fluid circulates. One benefit of the balloon design is that the balloon can collapse for insertion and expansion in situ. Circulating a heat exchange fluid through an expandable balloon provides increase surface area, and thus improved heat exchange capacity.
One drawback of vascular heat exchange catheters is that the amount of heat exchange possible is limited by the maximum temperature that the heat exchange fluid can be heated. Studies show that blood thickens when heated beyond 41xc2x0 C. Accordingly, vascular heat exchangers typically do not heat the blood beyond this temperature and, therefore, are limited in the ability to deliver heat transfer.
What is desired is an improved method and apparatus for heating a patient that can be used separate from, or in conjunction with, a vascular heat exchange catheter.
The present invention provides a method and apparatus for regulating the temperature of a patient through insertion of a heat exchange catheter into the colon.
In accordance with one aspect of the present invention, a method of regulating the temperature of a patient includes the steps of inserting a heat exchange catheter into a colon of a patient. The heat exchange catheter has a proximal end, a distal end, an inflow lumen, an outflow lumen, and an irrigation lumen.
The heat exchange catheter is inflated with at least one heat exchange fluid from a temperature control unit through the inflow lumen wherein the heat exchange fluid is circulated through the catheter.
In accordance with another aspect of the invention, the method of regulating the temperature of a patient includes the steps of irrigating the colon with an irrigation solution through the irrigation lumen of the heat exchange catheter, inflating the heat exchange catheter at least once, and then deflating the heat exchange catheter at least once to regulate efflux of irrigation solution.
The method of regulating the temperature of a patient includes regulating pressure inside the catheter body. The step of regulating pressure inside the catheter body includes actuating a valve on the outflow lumen.
In accordance with a further aspect of the invention, the method includes inserting the heat exchange catheter into the colon, irrigating the colon, inflating the heat exchange catheter, deflating the heat exchange catheter, and flushing the colon by removing the irrigation fluid from the colon.
In accordance with a further aspect of the present invention, a heat exchange catheter for inserting into the colon includes a catheter body having a proximal end, a distal end, an inflow lumen, an outflow lumen, and an irrigation lumen. A self-contained fluid circuit is in fluid communication with the inflow lumen and outflow lumen for effecting heat exchange with the catheter body. A heat exchange fluid is circulated through the catheter body.
The catheter body has an exterior surface that expands. In addition, the catheter body has at least one flex zone to permit conformance to the intestinal anatomy of the patient.
The present invention provides several advantages including avoiding the associate risk of infections and thrombosis involved with intra vascular devices where a solution is inserted into the blood stream resulting in change in a patient""s fluid balance. In addition, the body core can be heated and/or cooled at a rapid rate due to the large surface area within the colon.